This disclosure relates to seals and more particularly, to discrete active seal assemblies for sealing opposing surfaces.
Current methods and assemblies for sealing opposing surfaces such as doors and trunk lids, for example, include the use of flexible elastic membranes and structures that compress upon pressing into the opposing surfaces to close the gap between surfaces. Typical materials include various forms of elastomers, e.g., foams and solids, that are formed into structures having solid and/or hollow cross sectional structures. The geometries of the cross sections are varied and may range from circular forms to irregular forms having multiple cavities, channels, slots and/or extending vanes.
Sealing assemblies are typically utilized for sound, airflow, and/or fluid management. The seals generally are exposed to a variety of conditions. For example, for vehicle applications, door seals generally are exposed to a wide range of environmental conditions such as rain, snow, sun, humidity and temperature conditions, and the like. Current materials utilized for automotive seals are passive. That is, other than innate changes in modulus of the seal material due to aging and environmental stimuli, the stiffness and cross sectional geometries of the seal assemblies cannot be remotely changed or controlled on demand.
A problem with current seals is the tradeoff in seal effectiveness. Seal effectiveness can generally be increased by increasing the interface pressure and/or contact area of the seal. However, in sealing applications, such as in vehicle doors, the increased interface pressure and/or contact area by non-active seals results in increased door opening and closing efforts.
Accordingly, it is desirable to have active seal assemblies that can be controlled and remotely changed to alter the seal effectiveness, wherein the active seal assemblies change stiffness properties on demand, for example, by changing the material's elastic modulus, or geometry, for example by actively changing the cross-sectional shape of the seal. In this manner, in seal applications such as the vehicle door application noted above, door opening and closing efforts can be minimized yet seal effectiveness can be maximized.